JPH04366460A - Centering aligning device for disk - Google Patents

Abstract

PURPOSE:To reduce the thickness of a turntable by housing the first engaging surface in the turntable and third engaging surface in the first aligning member when a disk having a small-diameter center hole is put on the turn table. CONSTITUTION:When a disk 1b having a small-diameter center hole is put on a turntable 3, the center hole of the disk 1b is engaged with the engaging surface 21c for small-diameter of the second aligning member 21. When the center hole is engaged with the surface 21c, the thickness of the turntable 3 becomes thinner, because the wing-like section of the member 21 is put in the groove of the first aligning member 20 and gets into the turntable 3. Namely, when the members 20 and 21 are housed in the turntable 3, the thickness of the turntable 3 is reduced, because the engaging surface section of the member 21 is put in the notched section of the member 20. Therefore, the overall height of this disk aligning device can be reduced. In addition, the space below the turntable 3 becomes wider and the constitution of an optical pickup for reading recorded signals on the disk 1b can be made easier.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc centering device for an optical disc device for recording and reproducing information on a disc.

0002

2. Description of the Related Art Generally, in currently used audiovisual optical disc playback devices, when a disc is placed on a turntable, a centering member attached to a spindle engages with a center hole formed in the center of the disc. so that the center of the disk and the center of the spindle match. The disc is pressed against the turntable by the clamper, and the turntable is rotated in this state, causing the disc to rotate. When the disk reaches a predetermined rotational speed, an optical pickup reads the signals recorded on the disk and reproduces video and audio. In a device that can play both a 30 cm laser disc with video recorded on it and a 12 cm compact disc with audio recorded on it, there are two types of conical engagements, large and small, that engage with the center holes of different diameters on each disc. A centering member having a mating surface is disposed within the turntable. The structure is such that when a compact disc with a small diameter center hole is placed, the engagement surface for a laser disc with a large diameter center hole enters into the turntable.

A conventional disk centering device will be explained below. 8, 9, and 10 are cross-sectional views of conventional disk centering devices.

In FIG. 8, reference numeral 3 denotes a turntable carrying a disk 1a, which is fixed to a spindle 4 and rotated together by a spindle motor 5. In FIG. A centering member 2 is slidably engaged with the spindle 4 and has a large diameter engagement surface 2a and a small diameter engagement surface 2b. Both engaging surfaces have a conical shape concentric with the spindle 4. 6 is a centering spring inserted between the turntable 3 and the centering member 2, and 7 is a retainer attached to the spindle 4. 10 is a clamper to which a thrust ball 11 is fixed. 14 is a clamper holder to which a clamp spring 13 is fixed, and a thrust plate 12 is attached to the tip of the clamp spring 13. Thrust ball 11 and thrust plate 12
and constitute the thrust receiver of the clamper.

The operation of the disk centering device constructed as described above will be explained below.

First, FIG. 8 shows the operation of placing a disk 1a having a large diameter center hole.

When the disk 1a is placed on the turntable 3 from a position where the center of the disk 1a is shifted by a distance D from the center of the spindle 4 (indicated by a solid line), the disk 1a is placed in the state shown by a two-dot chain line. When the clamper holder 14 is lowered by a drive means (not shown), the clamper 10 comes into contact with the disk 1a. As the clamper holder 14 continues to descend, the clamp spring 13 is bent, and the clamper 14 presses the disk 1a by the spring force of the clamp spring 13 via the thrust plate 12 and thrust ball 11. disk 1a
The edge part of the center hole slides on the large diameter engagement surface part 2a,
The disk 1a moves to a position where the center of the disk 1a and the center of the spindle 4 coincide. Further, as the clamper holder 14 is lowered, the clamper 10 presses the disk 1a against the turntable 3, and clamping of the disk is completed. The clamped state is shown in FIG. In this state, the spindle motor 5 rotates the disk 1a.

Normally, the disk is placed on a tray (not shown) that moves in the direction of arrow A shown in FIG.
Misalignment of the center between the disk 1a and the spindle 4 occurs. In order to be clamped with their centers aligned, the width S1 of the large-diameter engagement surface portion 2a must be larger than the amount of deviation D between the center of the disk 1a and the center of the spindle 4. Furthermore, if the inclination of the large-diameter engagement surface portion 2a is made small, the disk will not slide on the engagement surface during clamping, so the inclination cannot be made very small. Therefore, the height S2 of the large-diameter inclined surface portion becomes large.

Next, FIG. 10 shows a clamped state when a disk 1b having a small diameter center hole is placed. The center hole of the disk 1b engages with the small diameter engagement surface portion 2b of the centering member 2. At this time, the large-diameter engagement surface portion 2a enters the inside of the turntable 3.

0010

However, in the conventional configuration described above, when the disk 1b having a small diameter center hole is placed on the turntable 3, the large diameter engagement surface 2a of the centering ring 2 is attached to the turntable. 3, the thickness of the turntable 3 needs to be T1 as shown in FIG. Since a space is required within the turntable 3 to accommodate the large-diameter engagement surface portion 2a, the turntable 3 becomes thick, and the entire device also becomes thick. In addition, since signals are recorded up to the vicinity of the turntable on a disk having a small diameter center hole, when playing back, the optical pickup 15 that reads the recorded signals on the disk reaches below the turntable 3, as shown in FIG. I need to come in. The thickness of the turntable 3 reduces the space into which the optical pickup 15 can fit, making it difficult to configure the optical pickup.

The present invention solves the above-mentioned conventional problems and aims to provide a thin turntable.

0012

[Means for Solving the Problems] In order to solve the above problems, the disk centering device of the present invention is fixed to a spindle shaft and driven to rotate integrally therewith, and has a turntable having a concave portion in the center of the disk support surface. A first centering surface that is movable in the spindle axial direction and is disposed in the recess of the turntable, the first engaging surface that engages with the center hole of the table and the first disk having a center hole formed on the outer periphery. a member, a second engagement surface that engages the center hole of the second disk having a center hole smaller than the center hole of the first disk, and a third engagement surface that engages the center hole of the first disk. The second centering member is movable in the spindle axial direction and is disposed in the recess of the turntable.

[0013]

[Operation] With the above-described structure, when a disk having a small diameter center hole is placed, the first engaging surface is stored in the turntable, and the third engaging surface is located at the first centering point. By being housed inside the member, the turntable can be made thinner.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A disk centering device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a disk centering device showing a first embodiment of the present invention, and FIGS.
and FIG. 4 is a cross-sectional view thereof.

In FIGS. 1 and 2, the first centering member 20 has the shape of a disk having a large-diameter engagement surface 20a on the outer periphery and three grooves 20b formed therein, and is slidable on the spindle 4. is attached to. The second centering member 21 is formed with three feather-like parts 21a having a large-diameter engagement surface part 21b and a small-diameter engagement surface part 21c. The width of the wing-like portion 21a is slightly smaller than the width of the groove 20b of the first centering member 20. Further, like the first centering member 20, it is slidably attached to the spindle 4. In FIG. 2, the height of the upper ridgeline of the large-diameter engagement surface portion 20a of the first centering member 20 is equal to the height of the upper ridgeline of the large-diameter engagement surface portion 20a of the second centering member 21.
It almost matches the height of the lower ridgeline of 1b. Further, the radius R1 is the same as or slightly smaller than the radius R2 of the lower ridgeline of the large-diameter engagement surface portion 21b. Others are the same as those described in the conventional example shown in FIG.

The operation of the disk centering device constructed as described above will be explained below.

FIG. 3 shows a disk 1a having a large diameter center hole.
FIG. The disc is placed on the turntable by the same operation as that described in the conventional example shown in FIGS. 8 and 9, and then the disc is placed in the clamped state shown in FIG. 3. The large-diameter engagement surface portion 20a of the first centering ring 20 engages with the center hole of the disk 1a. Since the large-diameter engagement surface portion 20a of the first centering ring 20 is formed concentrically with the spindle 4, the disk 1a
The center of the spindle 4 coincides with the center of the spindle 4.

Next, FIG. 4 shows a sectional view in a clamped state when a disk 1b having a small diameter center hole is mounted. The center hole of the disk 1b engages with the small diameter engagement surface 21c of the second centering member 21. At this time, the second centering member 21
The feather-like portion 21a of the groove 20b of the first centering member 20 (Fig. 1
) and enters the inside of the turntable 3. The thickness of the turntable 3 is T2 shown in FIG. 4, which is smaller than T1 of the conventional example explained in FIG.

FIG. 5 is an exploded perspective view of a disk centering device showing a second embodiment of the present invention, and FIGS. 6 and 7 are sectional views thereof.

In FIGS. 5 and 6, centering member 30
A large diameter engagement surface portion 30a and a small diameter engagement surface portion 30b are formed in the large diameter engagement surface portion 30a, and three protrusions 30c and a notch portion 30d are formed in the large diameter engagement surface portion 30a. Three fan-shaped holes 3a are formed in the turntable 3 fixed to the spindle 4, and the width thereof is slightly larger than the width of the protrusion of the centering ring 30. Others are the same as those described in the conventional example shown in FIG.

The operation of the disk centering device constructed as described above will be explained below.

First, FIG. 6 shows a sectional view of a disk 1a having a large diameter center hole in a clamped state. The operation from placing the disk 1a on the turntable 3 to this disk clamping state is the same as that described in the conventional example shown in FIGS. 8 and 9. At this time, the large-diameter engagement surface portion 30a of the centering ring 30 engages with the center hole of the disk 1a. Large diameter engagement surface portion 3 of centering ring 20
Since disk 0a is formed concentrically with spindle 4, the center of disk 1a and the center of spindle 4 coincide.

Next, FIG. 7 shows a sectional view in a clamped state when a disk 1b having a small diameter center hole is mounted. The center hole of the disk 1b engages with the small diameter engagement surface 21b of the second centering member 21. At this time, the large diameter engagement surface 30
a is a hole 3 in which a protrusion 30c is formed in the turntable 3;
a and enters the inside of the turntable 3. The thickness of the turntable 3 is T3 as shown in FIG.

As described above, according to this embodiment, effects equivalent to those of the first embodiment can be obtained.

[0026]

As described above, in the present invention, when the first centering member and the second centering member are stored in the turntable, the second centering member is inserted into the notch of the first centering member. By fitting the engaging surfaces of the turntable, the turntable becomes thinner, and the height of the entire disc centering device can be reduced. This allows the height of the entire centering device to be reduced. In addition, the space under the turntable becomes wider, and the configuration of the optical pickup for reading recorded signals on the disk becomes easier, which has great practical effects.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a disk centering device in a first embodiment of the present invention.

[Figure 2] Cross-sectional view of the same example

[Figure 3] Cross-sectional view of the same example

[Figure 4] Cross-sectional view of the same example

FIG. 5 is an exploded perspective view of a disk centering device in a second embodiment of the present invention.

[Figure 6] Cross-sectional view of the same example

[Figure 7] Cross-sectional view of the same example

[Figure 8] Cross-sectional view of a conventional disk centering device

[Fig. 9] Cross-sectional view of a conventional disk centering device

[Fig. 10] Cross-sectional view of a conventional disk centering device

[Explanation of symbols]

1a Disc 1b disk 20 First centering member 20a　Large diameter engagement surface part 21 Second centering member 21b Engagement surface for large diameter 21c Engagement surface part for small diameter 30 Centering member 30a　Large diameter engagement surface part 30b Engagement surface part for small diameter 3 Turntable

Claims (3)

[Claims] Claims: 1. A turntable fixed to a spindle shaft and rotationally driven integrally therewith, having a concave portion in the center of a disk supporting surface; and a first disk having a center hole, a first disk having a center hole; an engaging surface is formed on the outer circumference, a first centering member is movable in the axial direction of the spindle, and is disposed in the recess of the turntable; and a center hole smaller than the center hole of the first disk. The turntable has a second engagement surface that engages with the center hole of the second disk and a third engagement surface that engages with the center hole of the first disk, is movable in the axial direction of the spindle, and is movable in the spindle axial direction. and a second centering member disposed in the recess of the disc centering device, wherein when the first disc is placed, the first disc centering member
The centering of the disc is performed by the engaging surface and the third engaging surface, and when the second disc is placed, the centering of the disc is performed by the second engaging surface, and the third engaging surface is used to center the disc.
A disk centering device in which the engagement surface is housed inside the first centering member. 2. A turntable fixed to a spindle shaft and rotationally driven integrally therewith, having a recessed portion in the center of the disk supporting surface, and a first engagement member that engages with a center hole of a first disk having a center hole. a second engagement surface that engages a center hole of a second disk having a center hole smaller than the center hole of the first disk, the second disk is movable in the axial direction of the spindle, and A disk centering device comprising a centering member disposed in a recess of a table, wherein a part or the entire first engagement surface of the centering member is divided by a plurality of notches, and the centering member is divided by a plurality of notches. When the second disk is placed on the turntable, the divided first engagement surface fits into a plurality of holes formed in the recess of the turntable, so that the second disk is inserted into the turntable. A disc centering device that is stored. 3. The disk core according to claim 1, wherein the first centering member and the second centering member are moved in the axial direction of the spindle by a compressive force of a single spring disposed within the turntable. Output device.